composition testing

Author: winkerVSbecks

.storybook/preview.js

@@ -1,7 +1,10 @@
 import React from 'react';
 import { ChakraProvider } from '@chakra-ui/react';
+import { initialize, mswDecorator } from 'msw-storybook-addon';
 import { theme } from '../src/theme';
 
+initialize();
+
 export const parameters = {
   actions: { argTypesRegex: '^on[A-Z].*' },
   controls: {
@@ -25,4 +28,5 @@ export const decorators = [
       <Story />
     </ChakraProvider>
   ),
+  mswDecorator,
 ];

package.json

@@ -60,6 +60,11 @@
     "@storybook/manager-webpack5": "^6.5.3",
     "@storybook/node-logger": "^6.5.3",
     "@storybook/preset-create-react-app": "^4.1.0",
-    "@storybook/react": "^6.5.3"
+    "@storybook/react": "^6.5.3",
+    "msw": "^0.40.0",
+    "msw-storybook-addon": "^1.6.3"
+  },
+  "msw": {
+    "workerDirectory": "public"
   }
 }

public/mockServiceWorker.js

@@ -0,0 +1,338 @@
+/* eslint-disable */
+/* tslint:disable */
+
+/**
+ * Mock Service Worker (0.40.0).
+ * @see https://github.com/mswjs/msw
+ * - Please do NOT modify this file.
+ * - Please do NOT serve this file on production.
+ */
+
+const INTEGRITY_CHECKSUM = '02f4ad4a2797f85668baf196e553d929'
+const bypassHeaderName = 'x-msw-bypass'
+const activeClientIds = new Set()
+
+self.addEventListener('install', function () {
+  return self.skipWaiting()
+})
+
+self.addEventListener('activate', async function (event) {
+  return self.clients.claim()
+})
+
+self.addEventListener('message', async function (event) {
+  const clientId = event.source.id
+
+  if (!clientId || !self.clients) {
+    return
+  }
+
+  const client = await self.clients.get(clientId)
+
+  if (!client) {
+    return
+  }
+
+  const allClients = await self.clients.matchAll()
+
+  switch (event.data) {
+    case 'KEEPALIVE_REQUEST': {
+      sendToClient(client, {
+        type: 'KEEPALIVE_RESPONSE',
+      })
+      break
+    }
+
+    case 'INTEGRITY_CHECK_REQUEST': {
+      sendToClient(client, {
+        type: 'INTEGRITY_CHECK_RESPONSE',
+        payload: INTEGRITY_CHECKSUM,
+      })
+      break
+    }
+
+    case 'MOCK_ACTIVATE': {
+      activeClientIds.add(clientId)
+
+      sendToClient(client, {
+        type: 'MOCKING_ENABLED',
+        payload: true,
+      })
+      break
+    }
+
+    case 'MOCK_DEACTIVATE': {
+      activeClientIds.delete(clientId)
+      break
+    }
+
+    case 'CLIENT_CLOSED': {
+      activeClientIds.delete(clientId)
+
+      const remainingClients = allClients.filter((client) => {
+        return client.id !== clientId
+      })
+
+      // Unregister itself when there are no more clients
+      if (remainingClients.length === 0) {
+        self.registration.unregister()
+      }
+
+      break
+    }
+  }
+})
+
+// Resolve the "main" client for the given event.
+// Client that issues a request doesn't necessarily equal the client
+// that registered the worker. It's with the latter the worker should
+// communicate with during the response resolving phase.
+async function resolveMainClient(event) {
+  const client = await self.clients.get(event.clientId)
+
+  if (client.frameType === 'top-level') {
+    return client
+  }
+
+  const allClients = await self.clients.matchAll()
+
+  return allClients
+    .filter((client) => {
+      // Get only those clients that are currently visible.
+      return client.visibilityState === 'visible'
+    })
+    .find((client) => {
+      // Find the client ID that's recorded in the
+      // set of clients that have registered the worker.
+      return activeClientIds.has(client.id)
+    })
+}
+
+async function handleRequest(event, requestId) {
+  const client = await resolveMainClient(event)
+  const response = await getResponse(event, client, requestId)
+
+  // Send back the response clone for the "response:*" life-cycle events.
+  // Ensure MSW is active and ready to handle the message, otherwise
+  // this message will pend indefinitely.
+  if (client && activeClientIds.has(client.id)) {
+    ;(async function () {
+      const clonedResponse = response.clone()
+      sendToClient(client, {
+        type: 'RESPONSE',
+        payload: {
+          requestId,
+          type: clonedResponse.type,
+          ok: clonedResponse.ok,
+          status: clonedResponse.status,
+          statusText: clonedResponse.statusText,
+          body:
+            clonedResponse.body === null ? null : await clonedResponse.text(),
+          headers: serializeHeaders(clonedResponse.headers),
+          redirected: clonedResponse.redirected,
+        },
+      })
+    })()
+  }
+
+  return response
+}
+
+async function getResponse(event, client, requestId) {
+  const { request } = event
+  const requestClone = request.clone()
+  const getOriginalResponse = () => fetch(requestClone)
+
+  // Bypass mocking when the request client is not active.
+  if (!client) {
+    return getOriginalResponse()
+  }
+
+  // Bypass initial page load requests (i.e. static assets).
+  // The absence of the immediate/parent client in the map of the active clients
+  // means that MSW hasn't dispatched the "MOCK_ACTIVATE" event yet
+  // and is not ready to handle requests.
+  if (!activeClientIds.has(client.id)) {
+    return await getOriginalResponse()
+  }
+
+  // Bypass requests with the explicit bypass header
+  if (requestClone.headers.get(bypassHeaderName) === 'true') {
+    const cleanRequestHeaders = serializeHeaders(requestClone.headers)
+
+    // Remove the bypass header to comply with the CORS preflight check.
+    delete cleanRequestHeaders[bypassHeaderName]
+
+    const originalRequest = new Request(requestClone, {
+      headers: new Headers(cleanRequestHeaders),
+    })
+
+    return fetch(originalRequest)
+  }
+
+  // Send the request to the client-side MSW.
+  const reqHeaders = serializeHeaders(request.headers)
+  const body = await request.text()
+
+  const clientMessage = await sendToClient(client, {
+    type: 'REQUEST',
+    payload: {
+      id: requestId,
+      url: request.url,
+      method: request.method,
+      headers: reqHeaders,
+      cache: request.cache,
+      mode: request.mode,
+      credentials: request.credentials,
+      destination: request.destination,
+      integrity: request.integrity,
+      redirect: request.redirect,
+      referrer: request.referrer,
+      referrerPolicy: request.referrerPolicy,
+      body,
+      bodyUsed: request.bodyUsed,
+      keepalive: request.keepalive,
+    },
+  })
+
+  switch (clientMessage.type) {
+    case 'MOCK_SUCCESS': {
+      return delayPromise(
+        () => respondWithMock(clientMessage),
+        clientMessage.payload.delay,
+      )
+    }
+
+    case 'MOCK_NOT_FOUND': {
+      return getOriginalResponse()
+    }
+
+    case 'NETWORK_ERROR': {
+      const { name, message } = clientMessage.payload
+      const networkError = new Error(message)
+      networkError.name = name
+
+      // Rejecting a request Promise emulates a network error.
+      throw networkError
+    }
+
+    case 'INTERNAL_ERROR': {
+      const parsedBody = JSON.parse(clientMessage.payload.body)
+
+      console.error(
+        `\
+[MSW] Uncaught exception in the request handler for "%s %s":
+
+${parsedBody.location}
+
+This exception has been gracefully handled as a 500 response, however, it's strongly recommended to resolve this error, as it indicates a mistake in your code. If you wish to mock an error response, please see this guide: https://mswjs.io/docs/recipes/mocking-error-responses\
+`,
+        request.method,
+        request.url,
+      )
+
+      return respondWithMock(clientMessage)
+    }
+  }
+
+  return getOriginalResponse()
+}
+
+self.addEventListener('fetch', function (event) {
+  const { request } = event
+  const accept = request.headers.get('accept') || ''
+
+  // Bypass server-sent events.
+  if (accept.includes('text/event-stream')) {
+    return
+  }
+
+  // Bypass navigation requests.
+  if (request.mode === 'navigate') {
+    return
+  }
+
+  // Opening the DevTools triggers the "only-if-cached" request
+  // that cannot be handled by the worker. Bypass such requests.
+  if (request.cache === 'only-if-cached' && request.mode !== 'same-origin') {
+    return
+  }
+
+  // Bypass all requests when there are no active clients.
+  // Prevents the self-unregistered worked from handling requests
+  // after it's been deleted (still remains active until the next reload).
+  if (activeClientIds.size === 0) {
+    return
+  }
+
+  const requestId = uuidv4()
+
+  return event.respondWith(
+    handleRequest(event, requestId).catch((error) => {
+      if (error.name === 'NetworkError') {
+        console.warn(
+          '[MSW] Successfully emulated a network error for the "%s %s" request.',
+          request.method,
+          request.url,
+        )
+        return
+      }
+
+      // At this point, any exception indicates an issue with the original request/response.
+      console.error(
+        `\
+[MSW] Caught an exception from the "%s %s" request (%s). This is probably not a problem with Mock Service Worker. There is likely an additional logging output above.`,
+        request.method,
+        request.url,
+        `${error.name}: ${error.message}`,
+      )
+    }),
+  )
+})
+
+function serializeHeaders(headers) {
+  const reqHeaders = {}
+  headers.forEach((value, name) => {
+    reqHeaders[name] = reqHeaders[name]
+      ? [].concat(reqHeaders[name]).concat(value)
+      : value
+  })
+  return reqHeaders
+}
+
+function sendToClient(client, message) {
+  return new Promise((resolve, reject) => {
+    const channel = new MessageChannel()
+
+    channel.port1.onmessage = (event) => {
+      if (event.data && event.data.error) {
+        return reject(event.data.error)
+      }
+
+      resolve(event.data)
+    }
+
+    client.postMessage(JSON.stringify(message), [channel.port2])
+  })
+}
+
+function delayPromise(cb, duration) {
+  return new Promise((resolve) => {
+    setTimeout(() => resolve(cb()), duration)
+  })
+}
+
+function respondWithMock(clientMessage) {
+  return new Response(clientMessage.payload.body, {
+    ...clientMessage.payload,
+    headers: clientMessage.payload.headers,
+  })
+}
+
+function uuidv4() {
+  return 'xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxx'.replace(/[xy]/g, function (c) {
+    const r = (Math.random() * 16) | 0
+    const v = c == 'x' ? r : (r & 0x3) | 0x8
+    return v.toString(16)
+  })
+}